When a white dwarf explodes as a type Ia supernova, its death is so bright that its light can be detected across the Universe. A new observation using the Hubble Space Telescope identified the farthest type Ia supernova yet seen, at a distance of greater than 10 billion light-years. In the tradition of supernova surveys, this event was nicknamed for Woodrow Wilson, 28th President of the United States. The previous record-holder, Supernova Mingus, was about 350 million light-years closer to Earth.

White dwarfs are the remains of stars similar in mass to the Sun. Since such a star would have to live out its entire life to form a white dwarf, there are limits to how early in the Universe's history a type Ia supernova can explode. Only 8 white dwarf supernovas have been identified farther than 9 billion light-years away. (Some core-collapse supernovas, which are the explosions of very massive stars, have been seen farther than Supernova Wilson.) Since all such explosions happen in a similar way, cosmologists use them to measure the expansion rate of the Universe.

Astronomers found this violent event by comparing the light from several separate long exposures of the same patch of the sky, known as CANDELS (the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey). Bright as it was, the distance was so great that Supernova Wilson appeared as an enhancement of the luminosity of its host galaxy. The researchers subtracted the light of the galaxy without the supernova from the combined supernova-galaxy combination, then analyzed the residual light to identify it as type Ia.

The Universe was only a few billion years old when Supernova Wilson exploded, nearly as early as such an event could possibly occur. The early era of Supernova Wilson's explosion means it was likely the result of two white dwarfs merging rather than a single white dwarf exceeding its maximum mass. This is because the most massive white dwarfs require more time to form than the Universe's existence had provided.

Could this possible replace "Does a bear shit in the woods" type question? I mean, just how does/did a white dwarf die 10 billion years ago and how does that affect tomorrow? From now on I will be asking "Does a 10 billion year old what dwarf even give a shit?"

Could this possible replace "Does a bear shit in the woods" type question? I mean, just how does/did a white dwarf die 10 billion years ago and how does that affect tomorrow? From now on I will be asking "Does a 10 billion year old what dwarf even give a shit?"

How does it affect tomorrow? Hmmm, let's think. Understanding physics and the evolution of the universe better, how does that matter? Do you really need it spelled out for you? The more we know about what has happened, the more accurate our models of the universe, and the more we know about what WILL happen. In the future. As in, you know, the fate of the universe and minor stuff like that.

Two points:2. It's somewhat amazing that we can see a nova 10 billion light years away, but we still can't detect incoming asteroids. We need to get on that it's somewhat important.

Imagine you're walking around in an unlit field at night . Someone at the other end is walking around with a candle. Somewhere within 20 feet of you is a black bowling ball in the grass. Which is going to be easier to find?

Could this possible replace "Does a bear shit in the woods" type question? I mean, just how does/did a white dwarf die 10 billion years ago and how does that affect tomorrow? From now on I will be asking "Does a 10 billion year old what dwarf even give a shit?"

How does it affect tomorrow? Hmmm, let's think. Understanding physics and the evolution of the universe better, how does that matter? Do you really need it spelled out for you? The more we know about what has happened, the more accurate our models of the universe, and the more we know about what WILL happen. In the future. As in, you know, the fate of the universe and minor stuff like that.

Maybe the study of the aforementioned subject can also explain sarcasm for those failing to "get it"...

So we can see an incandescently angry white dwarf from ten billion lightyears away. The Prenda lawyers were just a few feet away from an incandescently angry Judge Wright, who is not a dwarf (and according to Aurich might have looked green that day).

The early era of Supernova Wilson's explosion means it was likely the result of two white dwarfs merging rather than a single white dwarf exceeding its maximum mass. This is because the most massive white dwarfs require more time to form than the Universe's existence had provided.

I learned that stars have shorter lives when they are more massive. E.g. Blue giants have a shorter life than our sun, which has a shorter life than a red dwarf.Is this different for white dwarfs?

In any case, the supernova would have been caused by a single white dwarf gaining mass from an companion star (until it reaches a critical mass and explodes) or the merger of 2 white dwarfs.Could anybody tell me which of these possibilities is more likely and why?

The recent Planck results demonstrates why especially SN 1a are important as distance proxies and what not. The Hubble constant and the DE estimates were both revised down, which put more, not the expected less, tension between CMB+BAO survey results and the SN survey results.

I haven't looked much at these objects, because "important" doesn't automatically translate to "interesting". But since people write more and more on the conflict between SN 1a models, I have picked up a merger reference that unifies 2 of, I think, at least 3 SN 1a subtypes. [ http://astrobites.org/2013/02/19/explod ... n-the-sky/ ] I read elsewhere that an 1ax type seems to be only predicted by a companion, and the dwarf likely survives in contrast to the "everything that can explode, does explode" as in the mergers pathway.

And now you know what I know in this. (>.<)

lab220 wrote:

I learned that stars have shorter lives when they are more massive. E.g. Blue giants have a shorter life than our sun, which has a shorter life than a red dwarf.Is this different for white dwarfs?

In any case, the supernova would have been caused by a single white dwarf gaining mass from an companion star (until it reaches a critical mass and explodes) or the merger of 2 white dwarfs.

Could anybody tell me which of these possibilities is more likely and why?

I think these two questions is actually this that the article describes in a vague way. The "most massive white dwarfs" would be close to the Chandrasekhar limit. From the paper:

"The two most likely SN Ia progenitor models are the single-degenerate scenario, where a white dwarf accretes matter from a main-sequence or giant companion, and the double-degenerate scenario, where SNe occur through the merging of two carbon-oxygen (C-O) white dwarfs.

A substantial difference between these mechanisms, however, is the typical time interval from progenitor formation to explosion; progenitors would likely take >~ 10^9 yr to reach the Chandrasekhar limit by mass transfer from a nondegenerate companion, but would more often take less time in a system of two C-O white dwarfs (for a recent review of SN Ia progenitors, see Wang & Han 2012).

The distribution of times between formation and explosion, known as the delay-time distribution (DTD), can therefore be used to set constraints on SN progenitor models."

Assuming I get the translation correct, it is this: two WD, which would be a frequent result of binary formation, would make a SN1a earlier than waiting for a companion to feed a WD to the Chandrasekhar limit. Eventually you hit the limit of the age of the universe, and sooner for the companion pathway. Sometime before that it would start to affect the observed distributions of occurrences and delay times.

If they can push these observations, maybe they can tell the difference. "However, with the fullsample of SNe at redshift greater than 1.5, new limits on the evolution of dark energy, the delay-time distribution, and the evolution of the SN Ia population will become possible."

[EDIT: Oh, now I see:] The "full sample" refers to a set of similar SNe in other pipelines, so they expect to be able to tell the likelihoods soon. Maybe the article refers to an unpublished estimate by some involved scientist, maybe it is hype. I can't see that it is in the current paper. (I can have missed it.)

Two points:2. It's somewhat amazing that we can see a nova 10 billion light years away, but we still can't detect incoming asteroids. We need to get on that it's somewhat important.

Imagine you're walking around in an unlit field at night . Someone at the other end is walking around with a candle. Somewhere within 20 feet of you is a black bowling ball in the grass. Which is going to be easier to find?

Maybe if I am just using my eyes, but asteroids emit infrared. We just don't have the detection grid to see them. The latest asteroid crashing into Russia might open some eyes and make this a priority though.

Imagine you're walking around in an unlit field at night . Someone at the other end is walking around with a candle. Somewhere within 20 feet of you is a black bowling ball in the grass. Which is going to be easier to find?

Maybe if I am just using my eyes, but asteroids emit infrared. We just don't have the detection grid to see them. The latest asteroid crashing into Russia might open some eyes and make this a priority though.

Using an infrared camera the candle would still be vastly easier to find. Depending on the emission characteristics of the bowling ball versus the grass, it might be just as difficult to find as with visible light. The most important point still applies to both the bowling ball and the candle, and the asteroid and the Supernova: The intrinsic brightness of the more distant object more than makes up for its distance, and light received is still greater.

We can still find them, however, and I agree it would be nice if we increased the priority.